Buildings.Fluid.Actuators.Valves

Information

Package Content

Name	Description
ThreeWayEqualPercentageLinear	Three way valve with equal percentage and linear characteristics
ThreeWayLinear	Three way valve with linear characteristics
TwoWayEqualPercentage	Two way valve with linear flow characteristics
TwoWayLinear	Two way valve with linear flow characteristics
TwoWayQuickOpening	Two way valve with linear flow characteristics

Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear

Information

Three way valve with equal percentage characteristics between port_1 and port_2 and linear opening characteristic between port_1 and port_2. Such opening characteristics were typical for valves from Landis & Gyr (now Siemens).

This model is based on the partial valve models Buildings.Fluid.Actuators.BaseClasses.PartialThreeWayValve and Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve. See Buildings.Fluid.Actuators.BaseClasses.PartialThreeWayValve for the implementation of the three way valve and see Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve for the implementation of the leakage flow or the regularization near the origin.

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Real	fraK	0.7	Fraction Kv(port_3->port_2)/Kv(port_1->port_2)
Real	l[2]	{0,0}	Valve leakage, l=Kv(y=0)/Kv(y=1)
Real	R	50	Rangeability, R=50...100 typically
Real	delta0	0.01	Range of significant deviation from equal percentage law
Flow Coefficient
CvTypes	CvData	Buildings.Fluid.Types.CvType...	Selection of flow coefficient
Real	Kv		Kv (metric) flow coefficient [m3/h/(bar)^(1/2)]
Real	Cv		Cv (US) flow coefficient [USG/min/(psi)^(1/2)]
Area	Av		Av (metric) flow coefficient [m2]
Pressure-flow linearization
Real	deltaM	0.02	Fraction of nominal flow rate where linearization starts, if y=1
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Pressure	dpValve_nominal		Nominal pressure drop of fully open valve, used if CvData=Buildings.Fluid.Types.CvTypes.OpPoint [Pa]
Pressure	dpFixed_nominal[2]	{0,0}	Nominal pressure drop of pipes and other equipment in flow legs at port_1 and port_3 [Pa]
Dynamics
Equations
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Formulation of energy balance
Dynamics	massDynamics	energyDynamics	Formulation of mass balance
Boolean	dynamicBalance	true	Set to true to use a dynamic balance, which often leads to smaller systems of equations
Nominal condition
Time	tau	10	Time constant at nominal flow for dynamic energy and momentum balance [s]
Filtered opening
Boolean	filteredOpening	true	= true, if opening is filtered with a 2nd order CriticalDamping filter
Time	riseTime	120	Rise time of the filter (time to reach 99.6 % of an opening step) [s]
Init	init	Modelica.Blocks.Types.Init.I...	Type of initialization (no init/steady state/initial state/initial output)
Real	y_start	1	Initial value of output
Initialization
AbsolutePressure	p_start	Medium.p_default	Start value of pressure [Pa]
Temperature	T_start	Medium.T_default	Start value of temperature [K]
MassFraction	X_start[Medium.nX]	Medium.X_default	Start value of mass fractions m_i/m [kg/kg]
ExtraProperty	C_start[Medium.nC]	fill(0, Medium.nC)	Start value of trace substances
ExtraProperty	C_nominal[Medium.nC]	fill(1E-2, Medium.nC)	Nominal value of trace substances. (Set to typical order of magnitude.)
Advanced
Boolean	from_dp	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	homotopyInitialization	true	= true, use homotopy method
Boolean	linearized[2]	{false,false}	= true, use linear relation between m_flow and dp for any flow rate
Nominal condition
Density	rhoStd	Medium.density_pTX(101325, 2...	Inlet density for which valve coefficients are defined [kg/m3]

Connectors

Type	Name	Description
FluidPort_a	port_1
FluidPort_b	port_2
FluidPort_a	port_3
input RealInput	y	Actuator position (0: closed, 1: open)
output RealOutput	y_actual	Actual valve position

Modelica definition

model ThreeWayEqualPercentageLinear 
  "Three way valve with equal percentage and linear characteristics"
    extends BaseClasses.PartialThreeWayValve(
      redeclare TwoWayEqualPercentage res1(R=R, delta0=delta0),
      redeclare TwoWayLinear res3);
  parameter Real R = 50 "Rangeability, R=50...100 typically";
  parameter Real delta0 = 0.01 
    "Range of significant deviation from equal percentage law";

equation 
  connect(inv.y, res3.y);
  connect(y_actual, inv.u2);
  connect(y_actual, res1.y);
end ThreeWayEqualPercentageLinear;

Buildings.Fluid.Actuators.Valves.ThreeWayLinear

Information

Three way valve with linear opening characteristic.

This model is based on the partial valve models Buildings.Fluid.Actuators.BaseClasses.PartialThreeWayValve and Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve. See Buildings.Fluid.Actuators.BaseClasses.PartialThreeWayValve for the implementation of the three way valve and see Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve for the implementation of the leakage flow or the regularization near the origin.

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Real	fraK	0.7	Fraction Kv(port_3->port_2)/Kv(port_1->port_2)
Real	l[2]	{0,0}	Valve leakage, l=Kv(y=0)/Kv(y=1)
Flow Coefficient
CvTypes	CvData	Buildings.Fluid.Types.CvType...	Selection of flow coefficient
Real	Kv		Kv (metric) flow coefficient [m3/h/(bar)^(1/2)]
Real	Cv		Cv (US) flow coefficient [USG/min/(psi)^(1/2)]
Area	Av		Av (metric) flow coefficient [m2]
Pressure-flow linearization
Real	deltaM	0.02	Fraction of nominal flow rate where linearization starts, if y=1
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Pressure	dpValve_nominal		Nominal pressure drop of fully open valve, used if CvData=Buildings.Fluid.Types.CvTypes.OpPoint [Pa]
Pressure	dpFixed_nominal[2]	{0,0}	Nominal pressure drop of pipes and other equipment in flow legs at port_1 and port_3 [Pa]
Dynamics
Equations
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Formulation of energy balance
Dynamics	massDynamics	energyDynamics	Formulation of mass balance
Boolean	dynamicBalance	true	Set to true to use a dynamic balance, which often leads to smaller systems of equations
Nominal condition
Time	tau	10	Time constant at nominal flow for dynamic energy and momentum balance [s]
Filtered opening
Boolean	filteredOpening	true	= true, if opening is filtered with a 2nd order CriticalDamping filter
Time	riseTime	120	Rise time of the filter (time to reach 99.6 % of an opening step) [s]
Init	init	Modelica.Blocks.Types.Init.I...	Type of initialization (no init/steady state/initial state/initial output)
Real	y_start	1	Initial value of output
Initialization
AbsolutePressure	p_start	Medium.p_default	Start value of pressure [Pa]
Temperature	T_start	Medium.T_default	Start value of temperature [K]
MassFraction	X_start[Medium.nX]	Medium.X_default	Start value of mass fractions m_i/m [kg/kg]
ExtraProperty	C_start[Medium.nC]	fill(0, Medium.nC)	Start value of trace substances
ExtraProperty	C_nominal[Medium.nC]	fill(1E-2, Medium.nC)	Nominal value of trace substances. (Set to typical order of magnitude.)
Advanced
Boolean	from_dp	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	homotopyInitialization	true	= true, use homotopy method
Boolean	linearized[2]	{false,false}	= true, use linear relation between m_flow and dp for any flow rate
Nominal condition
Density	rhoStd	Medium.density_pTX(101325, 2...	Inlet density for which valve coefficients are defined [kg/m3]

Connectors

Type	Name	Description
FluidPort_a	port_1
FluidPort_b	port_2
FluidPort_a	port_3
input RealInput	y	Actuator position (0: closed, 1: open)
output RealOutput	y_actual	Actual valve position

Modelica definition

model ThreeWayLinear "Three way valve with linear characteristics"
    extends BaseClasses.PartialThreeWayValve(
      redeclare TwoWayLinear res1,
      redeclare TwoWayLinear res3);

equation 
  connect(inv.y, res3.y);
  connect(y_actual, inv.u2);
  connect(y_actual, res1.y);
end ThreeWayLinear;

Buildings.Fluid.Actuators.Valves.TwoWayEqualPercentage

Information

Two way valve with an equal percentage valve opening characteristic.

This model is based on the partial valve model Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve. Check this model for more information, such as the leakage flow or regularization near the origin.

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Real	l	0.0001	Valve leakage, l=Kv(y=0)/Kv(y=1)
Real	R	50	Rangeability, R=50...100 typically
Real	delta0	0.01	Range of significant deviation from equal percentage law
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Pressure	dpValve_nominal		Nominal pressure drop of fully open valve, used if CvData=Buildings.Fluid.Types.CvTypes.OpPoint [Pa]
Pressure	dpFixed_nominal	0	Pressure drop of pipe and other resistances that are in series [Pa]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Flow Coefficient
CvTypes	CvData	Buildings.Fluid.Types.CvType...	Selection of flow coefficient
Real	Kv		Kv (metric) flow coefficient [m3/h/(bar)^(1/2)]
Real	Cv		Cv (US) flow coefficient [USG/min/(psi)^(1/2)]
Area	Av		Av (metric) flow coefficient [m2]
Pressure-flow linearization
Real	deltaM	0.02	Fraction of nominal flow rate where linearization starts, if y=1
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
Boolean	homotopyInitialization	true	= true, use homotopy method
Boolean	from_dp	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearized	false	= true, use linear relation between m_flow and dp for any flow rate
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Nominal condition
Density	rhoStd	Medium.density_pTX(101325, 2...	Inlet density for which valve coefficients are defined [kg/m3]
Dynamics
Filtered opening
Boolean	filteredOpening	true	= true, if opening is filtered with a 2nd order CriticalDamping filter
Time	riseTime	120	Rise time of the filter (time to reach 99.6 % of an opening step) [s]
Init	init	Modelica.Blocks.Types.Init.I...	Type of initialization (no init/steady state/initial state/initial output)
Real	y_start	1	Initial value of output

Connectors

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
input RealInput	y	Actuator position (0: closed, 1: open)
output RealOutput	y_actual	Actual valve position

Modelica definition

model TwoWayEqualPercentage 
  "Two way valve with linear flow characteristics"
  extends BaseClasses.PartialTwoWayValve;
  parameter Real R = 50 "Rangeability, R=50...100 typically";
  parameter Real delta0 = 0.01 
    "Range of significant deviation from equal percentage law";
initial equation 
 assert(l < 1/R, "Wrong parameters in valve model.\n"
               + "  Rangeability R = " + String(R) +  "\n"
               + "  Leakage flow l = " + String(l) +  "\n"
               + "  Must have l < 1/R = " + String(1/R));

equation 
  if homotopyInitialization then
     phi = homotopy(actual=Buildings.Fluid.Actuators.BaseClasses.equalPercentage(y_actual, R, l, delta0),
                    simplified=l + y_actual * (1 - l));
  else
     phi = Buildings.Fluid.Actuators.BaseClasses.equalPercentage(y_actual, R, l, delta0);
  end if;
end TwoWayEqualPercentage;

Buildings.Fluid.Actuators.Valves.TwoWayLinear

Information

Two way valve with linear opening characteristic.

This model is based on the partial valve model Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve. Check this model for more information, such as the leakage flow or regularization near the origin.

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Real	l	0.0001	Valve leakage, l=Kv(y=0)/Kv(y=1)
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Pressure	dpValve_nominal		Nominal pressure drop of fully open valve, used if CvData=Buildings.Fluid.Types.CvTypes.OpPoint [Pa]
Pressure	dpFixed_nominal	0	Pressure drop of pipe and other resistances that are in series [Pa]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Flow Coefficient
CvTypes	CvData	Buildings.Fluid.Types.CvType...	Selection of flow coefficient
Real	Kv		Kv (metric) flow coefficient [m3/h/(bar)^(1/2)]
Real	Cv		Cv (US) flow coefficient [USG/min/(psi)^(1/2)]
Area	Av		Av (metric) flow coefficient [m2]
Pressure-flow linearization
Real	deltaM	0.02	Fraction of nominal flow rate where linearization starts, if y=1
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
Boolean	homotopyInitialization	true	= true, use homotopy method
Boolean	from_dp	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearized	false	= true, use linear relation between m_flow and dp for any flow rate
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Nominal condition
Density	rhoStd	Medium.density_pTX(101325, 2...	Inlet density for which valve coefficients are defined [kg/m3]
Dynamics
Filtered opening
Boolean	filteredOpening	true	= true, if opening is filtered with a 2nd order CriticalDamping filter
Time	riseTime	120	Rise time of the filter (time to reach 99.6 % of an opening step) [s]
Init	init	Modelica.Blocks.Types.Init.I...	Type of initialization (no init/steady state/initial state/initial output)
Real	y_start	1	Initial value of output

Connectors

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
input RealInput	y	Actuator position (0: closed, 1: open)
output RealOutput	y_actual	Actual valve position

Modelica definition

model TwoWayLinear "Two way valve with linear flow characteristics"
  extends BaseClasses.PartialTwoWayValve;

equation 
  phi = l + y_actual * (1 - l);
end TwoWayLinear;

Buildings.Fluid.Actuators.Valves.TwoWayQuickOpening

Information

Two way valve with a power function for the valve opening characteristic. Valves that need to open quickly typically have such a valve characteristics.

This model is based on the partial valve model Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve. Check this model for more information, such as the leakage flow or regularization near the origin.

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Real	l	0.0001	Valve leakage, l=Kv(y=0)/Kv(y=1)
Real	alp	2	Parameter for valve characteristics, alp>0
Real	delta0	0.01	Range of significant deviation from power law
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Pressure	dpValve_nominal		Nominal pressure drop of fully open valve, used if CvData=Buildings.Fluid.Types.CvTypes.OpPoint [Pa]
Pressure	dpFixed_nominal	0	Pressure drop of pipe and other resistances that are in series [Pa]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Flow Coefficient
CvTypes	CvData	Buildings.Fluid.Types.CvType...	Selection of flow coefficient
Real	Kv		Kv (metric) flow coefficient [m3/h/(bar)^(1/2)]
Real	Cv		Cv (US) flow coefficient [USG/min/(psi)^(1/2)]
Area	Av		Av (metric) flow coefficient [m2]
Pressure-flow linearization
Real	deltaM	0.02	Fraction of nominal flow rate where linearization starts, if y=1
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
Boolean	homotopyInitialization	true	= true, use homotopy method
Boolean	from_dp	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearized	false	= true, use linear relation between m_flow and dp for any flow rate
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Nominal condition
Density	rhoStd	Medium.density_pTX(101325, 2...	Inlet density for which valve coefficients are defined [kg/m3]
Dynamics
Filtered opening
Boolean	filteredOpening	true	= true, if opening is filtered with a 2nd order CriticalDamping filter
Time	riseTime	120	Rise time of the filter (time to reach 99.6 % of an opening step) [s]
Init	init	Modelica.Blocks.Types.Init.I...	Type of initialization (no init/steady state/initial state/initial output)
Real	y_start	1	Initial value of output

Connectors

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
input RealInput	y	Actuator position (0: closed, 1: open)
output RealOutput	y_actual	Actual valve position

Modelica definition

model TwoWayQuickOpening 
  "Two way valve with linear flow characteristics"
  extends BaseClasses.PartialTwoWayValve;
  parameter Real alp = 2 "Parameter for valve characteristics, alp>0";
  parameter Real delta0 = 0.01 "Range of significant deviation from power law";
protected 
   parameter Real alpInv = 1/alp;
equation 
  if homotopyInitialization then
     phi = homotopy(actual=l + Modelica.Fluid.Utilities.regPow(y_actual, alpInv, delta0) * (1 - l),
                    simplified=l + y_actual * (1 - l));
  else
     phi = l + Modelica.Fluid.Utilities.regPow(y_actual, alpInv, delta0) * (1 - l);
  end if;
end TwoWayQuickOpening;